Molybdenum disulfide flotation antifoam

ABSTRACT

An antifoam and process for the separation of molybdenum values associated with predominantly copper ores of the sulfide type. The antifoam, which is primarily directed to laundering or cleaning stages in the moly cycle, consists of a utilization of 1-60 ppm of a polyoxyethylene glycol ester in a hydrocarbon diluent per ton of ore. The oxyethylene fraction has a value of about 100-2,000 and an optimum value of 400, and the fatty acid fraction is selected from C14 - C22 acids. A preferred antifoam is polyethylene glycol 400 dioleate (P.E.G. 400 dioleate) in kerosene or isoparaffin oil as the diluent. HLB values for the P.E.G. antifoam range from 5-12 with a preferred value of 5-10 for the dioleate.

United States Patent 1 1 Michalski et al.

[451 Sept. 24, 1974 MOLYBDENUM DISULFIDE FLOTATION ANTIFOAM [75] Inventors: Raymond J. Michalski, Riverdale;

John T. Cantwell, Oak Lawn, both of I11.

[73] Assignee: Nalco Chemical Company, Chicago,

Ill.

22 Filed: Nov. 24, '1972 [21] Appl. N0.: 309,013

[52] US. Cl. 209/167, 209/3 [51] Int. Cl B03d 1/06 [58] Field of Search 209/166, 167; 252/61, 321, 252/319 [56] References Cited UNITED STATES PATENTS 2,259,420 10/1941 Mills 209/166 2,302,338 11/1942 Moeller 2,312,466 3/1943 Erickson 2,362,432 11/1944 Cuhn 2,664,199 12/1953 Barker 2,668,150 2/1954 Luvisi 3,313,412 4/1967 Bloom 3,539,002 11/1970 Last 209/167 X Primary Examiner-Robert Halper Attorney, Agent, or Firm-John G. Premo; John S. Roberts, Jr.; James F. Lambe [5 7] ABSTRACT An antifoam and process for the separation of molybdenum values associated with predominantly copper ores of the sulfide type. The antifoam, which is primarily directed to laundering or cleaning stages in the moly cycle, consists of a utilization of 1-60 ppm of a polyoxyethylene glycol ester in a hydrocarbon diluent per ton of ore. The oxyethylene fraction has a value of about 1002,000 and an optimum value of 400, and the fatty acid fraction is selected from C, C, acids. A preferred antifoam is polyethylene glycol 400 dioleate (P.E.G. 400 dioleate) in kerosene or isoparaffin oil as the diluent. HLB values for the PEG. antifoam range from 5-12 with a preferred value of 5-10 for the dioleate.

5 Claims, N0 Drawings MOLYBDENUM DISULFIDE FLOTAT'ION ANTIFOAM The present invention relates to an antifoam and process specifically utilized in the separation of molybdenite or molybdenum disulfide from predominantly copper ores of the sulfide type. The separation of molybdenum quantities from copper in mixtures offers commercial advantages where originally the production was directed to the recovery only of copper values. In this process in the molybdenite cycle, there occurs one or more cleaner or launderer steps which are set out by example graphically in the figures of U.S. Pat. No. 2,664,199 Barker et al.

The recovery of the molybdenite involves the depression of copper which is usually achieved by the use of a ferricyanide reagent or utilization of the inorganics exemplified by the Nokes reagent of P, As, or Sb, divalent S and an inorganic cation and commonly using P S NaOI-l; see'U.S. Pat. No. 2,492,936 Nokes et al. Modified Nokes reagents have been utilized as for example U.S. Pat. No. 2,957,576 Henderson (Anaconda); U.S. Pat. No. 3,375,924 Corbett et al. (Miami Copper), the latter raises the pH of the usual Nokes to at least 11.4; and U.S. Pat. No. 3,435,952 Corbett (Miami Copper). Examples of additional methods of floating the molybdenite by depressing the copper are set out in U.S. Pat. No. 3,351,193 Martinez (American Cyanamid) and other copper depressants are described post.

In the so-called cleaning or launderer steps of the process for recovering molybdenite, it has been found that an abnormal or unusual amount of foam occurs which vitiates some of the commercial advantages of the process and to obviate this foam this invention adds 1-60 ppm per ton of ore or a preferred amount of 40-50 ppm of a polyethylene glycol monoor di-ester wherein the oxyethylene or ethoxy repeating unit has a value of from about 100 to 2,000. The acid fraction may be selected from fatty acids containing 14-22 carbon atoms, such as oleic acid, stearic acid, palmitic acid, ricinoleic acid, lauric acid, myristic acid, cerotic acid, and linoleic acid. A most preferred ester is the dioleate of polyethylene glycol having a molecular weight of about 400 (RFC. 400). Operable P.E.G. esters have been found to have an HLB value (Hydrophilel- Lypophile Balance) of 5-12. From a consideration of the fact that the l-ILB scale is from 1-20 with the values over indicating greater hydrophilic attraction, the specificity of the invention is noted. A summary of values of surfactants as in emulsions is given in the Encyclopedia of Chemical Technology 11, Volume 8, pages 128-130. The following values are noted at page 129 of ECT and also from McCutcheons Detergents and Emulsifiers, 1972 Annual:

I-ILB 400 monooleate 400 monostearate 100 monoricinoleate 200 dilaurate 400 dioleate I00 monolaurate 1500 dioleate 600 dioleate The P.E.G. ester when used in this specification and claims is defined as a 'monoor di-ester containing C -C and may be a blend of esters wherein such blend has a composite HLB value within the limits stated as, for example, a 50/50 blend of polyethylene glycol 400 dioleate and polyethylene glycol 400 dilaurate.

P.E.G. esters containing defoamers for other purposes are known; for example, U.S. Pat. No. 2,715,614 Snook (Nopco) utilizes such esters generally but disclosed for papermaking. U.S. Pat. No. 2,727,009 Jursich (Nalco) utilizes P. E.G. 400 dilaurate as an emulsifying agent in sugar recovery. In U.S. Pat. No. 3,198,744 Lamont (Nalco), the P.E.G. 400 dioleate is used as an emulsifier for an antifoam composition in the paper industry.

The problems of the above prior art differ from separation of the molybdenite by depressing the associated copper sulfide values.

The general process is discussed in:

A.M. Gaudin, Flotation, 2d edition, McGraw-Hill,

1957, pages 449-457;

American Institute of Metallurgical Engineering, Froth Flotation, 50th Anniversary Volume, 1962, AIME, Chapter 16, pages 363-426.

As stated above, a most preferred reagent is the polyoxyethylene glycol 400 dioleate and the oxyethylene portion may vary from about l00-2,000. This compound and others noted previously, when utilized in the process in a laundering step, serve as a spreading agent and form a thin layer on the water which then is dissipated throughout the body of the pulp, modifying the bubbles in the interface. The action of the antifoam has a relatively short life so that the moly collector following the launderer is not disturbed.

The operation of the present preferred antifoams endows to the circuit in the launderer or launderers the capacity to reduce the froth level but also has a short duration of only about 2 seconds. Additionally, the antifoam serves to minimize any reduced oil buildup so as to prevent the copper particles from becoming oil smeared and thus renders the copper particles hydrophobic as well as stabilizing the froth. Finally, the present antifoams display the quality of decreasing froth stability slightly or making the froth slightly unstable so that the trapped copper particles within the froth drop out back into the slurry and thus from bank to bank or stage to stage minimize the copper carryover to the next flotation step.

The basic procedures which depress the copper sulfide minerals and float the molybdenite all include the use of a diluent liquid hydrocarbon which functions as a smearing collector for the molybdenite. In the present process an oil carrier such as an isoparaffin, kerosene, mineral seal oil, deoderized kerosene, and paraffin oil may be utilized. Of particular interest and effectiveness is the combination of RES. 400 dioleate diluted 20/80 with deoderized kerosene.

In the usual case of the predominantly copper mineral, the copper is floated first and subsequently the remaining pulp containing the copper collector is laundered or washed in one or more steps prior to the molybdenite flotation procedure. A typical operational molybdenum circuit or cycle consists of one rougher bank, two scavenger banks, and six cleaner banks or stages, and molybdenum is recovered from the last or No. 6 cleaner bank. Typical reagents utilized in the moly circuit are:

a. sodium hypochlorite to render the xanthate ion inactive b. sulfuric acid pH control 0. potassium ferricyanide to depress the copper d. antifoam In the utilization of this, the tailings from each step are recirculated upstream in the previous step of the circuit for maximum moly recovery except in the case of the rougher and second scavenger tailings which go to a final copper concentrate thickener. The feed entering the moly circuit is approximately percent solids.

It is in the laundering or cleaning banks where the present polyoxyethylene glycol esters are utilized to suppress foam. In the subsequent molybdenum flotation steps sufficient copper depressants may be utilized such as alkali sulfides, cyanides, cuprocyanides, ferrocyanides, or ferricyanides. It has been found that the utilization of the present antifoams in the cleaning stages assists in reducing the amount of copper passing through to the final recovery of molybdenum sulfide, and it is for this reason that multiple cleaning or launderer stages are utilized.

EXAMPLE I In a molybdenum flotation process utilizing in the molybdenum cycle two stages of launderer, an antifoam composition consisting of 20 parts by weight P.E.G. 400 dioleate and 80 parts by weight of deoderized kerosene in a concentration of 250 ppm was introduced into each launderer stage. Visual inspection at EXAMPLE II In a moly sulfide cycle or circuit following the flotation of the copper values, a circuit was utilized consisting of one rougher bank, two scavenger banks, and six cleaner banks. The final product molybdenum is the froth from No. 6 cleaner. In the process, sodium hypochlorite was utilized to render the xanthate ion inactive which had been previously utilized for copper recovery and potassium ferricyanide was utilized to depress the copper in this moly cycle. Additionally, sulfuric acid was utilized for pH control and 50 ppm of polyoxyethylene 400 dilaurate was added as an antifoam in the circuit. The result was a decrease in the amount of copper recovered in the latter stages evidenced by the visual appearance of a gray color substituted for a previous greenish color in the cleaning or launderer stage of a surfeit of foam.

The embodiments of this invention in which an exclusive property or privilege is claimed are defined as follows:

1. In the recovery process of molybdenite from associated copper values froth flotation where the copper values are depressed, the step of adding to the launderer stage of the molybdenum recovery cycle an antifoam consisting of about 1-60 ppm per ton of ore of a polyoxyethylene glycol ester wherein the oxyethylene repeating unit has a molecular weight of from about 2,000 and the acid fraction is selected from fatty acids containing 14-22 carbon atoms and a hydrocarbon diluent and subsequently floating off the molybdenite.

2. Inthe process according to claim 1, the step of adding an antifoam consisting of about 40-50 ppm of polyoxyethylene glycol 400 dioleate and kerosene as a hydrocarbon diluent.-

3. In the process according to claim 1, the step of adding an antifoam consisting of about 40-50 ppm of polyoxyethylene glycol 400 dioleate and isoparaffin oil as a hydrocarbon diluent.

4. In the process according to claim 1, the step of adding an antifoam consisting of a polyoxyethylene ester having an HLB range of from 5-12.

5. In the process according to claim 1, the step of adding an antifoam consisting of about 40-50 ppm of a polyoxyethylene oleate ester having an HLB value of from 5-10. 

2. In the process according to claim 1, the step of adding an antifoam consisting of about 40-50 Ppm of polyoxyethylene glycol 400 dioleate and kerosene as a hydrocarbon diluent.
 3. In the process according to claim 1, the step of adding an antifoam consisting of about 40-50 ppm of polyoxyethylene glycol 400 dioleate and isoparaffin oil as a hydrocarbon diluent.
 4. In the process according to claim 1, the step of adding an antifoam consisting of a polyoxyethylene ester having an HLB range of from 5-12.
 5. In the process according to claim 1, the step of adding an antifoam consisting of about 40-50 ppm of a polyoxyethylene oleate ester having an HLB value of from 5-10. 